miR-196b调控胶质瘤相关癫痫发生发展的分子机制

Glioma is the most common form of brain tumors, in which low-grade glioma has a relatively higher incidence than glioblastoma for Chinese patients.Most adult patients with low-grade glioma experience epileptic seizures at disease onset. Seizure plays an important role in their quality of life.In our previous studies, whole-genome microRNA profiling was performed and revealed that miR-196b was involed in epileptogenesis and associated with patients' seizure control after surgery. To date, the molecular mechanisms of miR-196b in the pathogenesis of glioma-related epilepsy have not yet been elucidated. Based on our previous study, we propose a hypothesis that target genes regulated by miR-196b may induce cell proliferation, change neurotransmitter level in tumor microenvironment, disturb the electrophysiology activity of normal neurons, and contribute to epileptogenesis.To verify the hypothesis above, we intend to analyze the clinical significance of miR-196b in a large number of clinical specimens and explore its functional role in gliomas via a series of molecular biologic avenues both in vitro and in vivo, such as qRT-PCR, immunostaining, in vitro and in vivo assay, neurophysiological monitoring et al. In summary, based on the idea of translational medicine, the present study aims to investigate the potential role of miR-196b in the pathogenesis of glioma-related epilepsy and provide insight into the molecular diagnosis and target therapy of tumor-related epilepsy.

脑胶质瘤是最常见的颅内肿瘤，国人更以低级别胶质瘤发病率高。低级别胶质瘤患者常以癫痫起病，癫痫是困扰低级别脑胶质瘤患者的主要临床问题。我们前期研究利用全基因组miRNA表达谱芯片分析低级别脑胶质瘤的临床样本，筛选并鉴定出miR-196b参与调控胶质瘤相关癫痫的发生并与患者的癫痫预后密切相关，但其具体机制尚未明确。基于前期研究结果，我们提出假说：miR-196b调控细胞增殖相关基因的表达，改变微环境中神经递质的释放与摄取，干扰神经元的电生理活动，从而影响癫痫的发生发展。为了验证这一假说，我们将通过大规模的临床样本、体外细胞系和动物成瘤模型，采用实时定量PCR、免疫组化检测、体外细胞系功能实验、神经电生理监测等技术手段，从分子、细胞、组织以及临床整体水平探讨miR-196b在胶质瘤相关癫痫发生发展中的作用。本研究将本着转化医学的理念，密切结合临床，从分子水平揭示胶质瘤相关癫痫的发病机理。

转录因子HOXC8，miRNA-196b著名的靶基因，在多种肿瘤中过表达，调节许多重要基因参与了许多重要的功能。然而，HOXC8在胶质瘤中的作用仍不清楚。基于中国胶质瘤基因组数据库（CGGA），HOXC8表达与肿瘤级别呈正相关。小干扰RNA（si-HOXC8）用于下调HOXC8 mRNA以及蛋白表达水平用来验证HOXC8对胶质瘤细胞增殖、迁移和侵袭的影响。高水平的患者HOXC8有较差的总生存期（OS）。GSEA和KEGG通路分析表明HOXC8是与细胞周期、细胞外基质受体和上皮间质转化（EMT）有关。在U251和LN229胶质瘤细胞敲除HOXC8的表达量后，细胞生长明显降低，迁移和侵袭也明显降低。有趣的是，HOXC8的减少引起可钙黏蛋白11（CDH11）的蛋白，一个经典的EMT相关标志物，表达量下降。总之，HOXC8显著影响胶质瘤细胞的增殖、迁移和侵袭能力，可能是胶质瘤的诊断和治疗的新靶点。